Java Utililty Methods XML Node Previous

int countElementsBefore(Node node, String tagName)
Count the DOM element nodes before the supplied node, having the specified tag name, not including the node itself.

Node parent = node.getParentNode();
if (parent == null) {
 System.out.println("Cannot count nodes before [" + node + "]. [" + node + "] has no parent.");
 return 0;
NodeList siblings = parent.getChildNodes();
int count = 0;
int siblingCount = siblings.getLength();
...

int countElementsBefore(Node node, String tagName)
Count the DOM element nodes before the supplied node, having the specified tag name, not including the node itself.

Node parent = node.getParentNode();
NodeList siblings = parent.getChildNodes();
int count = 0;
int siblingCount = siblings.getLength();
for (int i = 0; i < siblingCount; i++) {
 Node sibling = siblings.item(i);
 if (sibling == node) {
 break;
...

List getAncesters(Node node)
Get a list of ancester nodes starting from the Document till the node.

List list = new ArrayList();
while (node != null) {
 list.add(node);
 if (node instanceof Document) {
 break;
 node = node.getParentNode();
if (node == null) {
 return null;
Collections.reverse(list);
list.add(null); 
return list;

Node getAncestor(Node node, String ancestorName)
If node has an ancestor with name ancestorName, return that ancestor.

Node p = node;
while ((p = p.getParentNode()) != null) {
 if (p.getNodeName().equals(ancestorName))
 return p;
return null;

Node getAncestorNode(Node visualNode, String tagName)
get Ancestor Node

if (tagName == null)
 return null;
Node element = visualNode;
while (true) {
 if (tagName.equalsIgnoreCase(element.getNodeName())) {
 return element;
 element = element.getParentNode();
...

List getAncestors(Node node)
get Ancestors

final List<Node> ancestors = new ArrayList<Node>();
while (node != null) {
 ancestors.add(node);
 node = node.getParentNode();
return ancestors;

Node getPrevious(final Node current, final boolean sameName)
get Previous

String name = null;
if (sameName) {
 name = current.getNodeName();
int type = current.getNodeType();
return getPrevious(current, name, type);

Node getPrevious(Node node)
Get the previous node in a DFS preorder traversal

Node previous;
if (node == null)
 return null;
if ((previous = node.getPreviousSibling()) != null) {
 for (; previous.getLastChild() != null; previous = previous.getLastChild()) {
 return previous;
return node.getParentNode();

String getPreviousComment(Node element)
get Previous Comment

while (element.getPreviousSibling() != null) {
 Node prev = element.getPreviousSibling();
 if (prev.getNodeType() == Node.COMMENT_NODE) {
 return prev.getTextContent();
 } else if (prev.getNodeType() == Node.TEXT_NODE) {
 return getPreviousComment(prev);
 } else if (prev.getNodeType() == Node.ELEMENT_NODE) {
 return null;
...

String getPreviousComment(Node element)
Gets the previous comment.

while (element.getPreviousSibling() != null) {
 Node prev = element.getPreviousSibling();
 if (prev.getNodeType() == Node.COMMENT_NODE) {
 return prev.getTextContent();
 } else if (prev.getNodeType() == Node.TEXT_NODE) {
 return getPreviousComment(prev);
 } else if (prev.getNodeType() == Node.ELEMENT_NODE) {
 return null;
...